Rotary printing machines usually use drive gearing which includes at least some gears with inclined or spiral teeth. Upon axial shifting of a cylinder, lateral as well as circumferential register can be changed. It has also been proposed to provide rotary printing machines with forme and blanket cylinders which do not have attachment grooves for printed image carriers and/or rubber blankets but, rather, in which the image carriers and/or rubber blankets are applied in the form of circumferentially continuous sleeves about the respective cylinders.
European Patent 0 019 697, as an example, illustrates a rotary offset printing machine having a register adjustment arrangement located at the operating side I of the printing machine. Usually, lateral and circumferential register in rotary printing machines is obtained by axially shifting and rotating the cylinder, customarily the plate or forme cylinder of the printing machine. Register adjustment, thus, is possible from one side, the operator side I only, and all drive gearing and the like, for example in form of gear trains, is located on the machine side II.
The arrangement is satisfactory for many rotary printing machines. For various reasons, however, placing the register adjustment control system at the operator side is not suitable, or even impossible. This is particularly so when rotary printing machines are used in which the cylinders do not have clamping grooves but, rather, in which the respective cylinders carry circumferentially continuous sleeves. If so, one side of the printing machine must be freely accessible so that the sleeves can be applied on the cylinders. The drive side of the machine is unsuitable because it would require disassembly of numerous gears in order to provide axial access to the respective cylinders. The referenced U.S. Pat. No. 4,807,427 shows a printing machine in which one side wall is formed with an opening sufficient to permit re-sleeving of a cylinder.
It is an object of the present invention to provide a rotary printing machine which has an apparatus or system to adjust the lateral and circumferential register and which is so constructed that the operator side is not needed to provide for the adjustment or register control arrangement. Thus, adjustments should be capable of being made only from the drive side of the machine, so that the operator side will not be required for any adjustment apparatus or system.
Briefly, a spiral gear coupled to a cylinder which is to be adjustable with respect to a circumferential and axial register position, for example the plate cylinder of a rotary offset printing machine, is coupled to an axially shiftable spiral gearing. The spiral gear can be driven from another cylinder, or from the drive train. This spiral gear is in engagement with another spiral gear which is coupled to a gear having axially arranged teeth, for example by a dual gear ring structure. The dual gear ring structure, also, is axially shiftable, and coupled to a further axial gear which is seated in predetermined axial and angular position on the shaft of the cylinder to be adjusted, and splined thereto, so as to transmit rotary power. Thus, upon axial adjustment, respectively, of the shaft of the respective cylinder, the lateral register can be adjusted; upon axial adjustment of the coupled spiral gear - axial gear arrangement, the circumferential register of the respective cylinder can be adjusted.
The system has the advantage that the drive connection to the printing machine cylinders requires only minimum modification to, also, provide for register adjustment of a cylinder with respect to a drive, both in circumferential and axial direction, while leaving the operator side of the machine unencumbered by any adjustment mechanism.